MMDVMHost-Private/DMRSync.cpp
2016-01-14 18:45:04 +00:00

155 lines
4.5 KiB
C++

/*
* Copyright (C) 2015 by Jonathan Naylor G4KLX
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "DMRSync.h"
#include "DMRDefines.h"
#include <cstdio>
#include <cassert>
const unsigned int BITS_LOOKUP[] = {0U, 1U, 1U, 2U, 1U, 2U, 2U, 3U, 1U, 2U, 2U, 3U, 2U, 3U, 3U, 4U,
1U, 2U, 2U, 3U, 2U, 3U, 3U, 4U, 2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U,
1U, 2U, 2U, 3U, 2U, 3U, 3U, 4U, 2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U,
2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U, 3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U,
1U, 2U, 2U, 3U, 2U, 3U, 3U, 4U, 2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U,
2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U, 3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U,
2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U, 3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U,
3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U, 4U, 5U, 5U, 6U, 5U, 6U, 6U, 7U,
1U, 2U, 2U, 3U, 2U, 3U, 3U, 4U, 2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U,
2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U, 3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U,
2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U, 3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U,
3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U, 4U, 5U, 5U, 6U, 5U, 6U, 6U, 7U,
2U, 3U, 3U, 4U, 3U, 4U, 4U, 5U, 3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U,
3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U, 4U, 5U, 5U, 6U, 5U, 6U, 6U, 7U,
3U, 4U, 4U, 5U, 4U, 5U, 5U, 6U, 4U, 5U, 5U, 6U, 5U, 6U, 6U, 7U,
4U, 5U, 5U, 6U, 5U, 6U, 6U, 7U, 5U, 6U, 6U, 7U, 6U, 7U, 7U, 8U};
const unsigned int THRESHOLD = 4U;
CDMRSync::CDMRSync()
{
}
CDMRSync::~CDMRSync()
{
}
DMR_SYNC_TYPE CDMRSync::matchDirectSync(const unsigned char* bytes) const
{
assert(bytes != NULL);
unsigned int diffs = compareBytes(bytes + 13U, DIRECT_SLOT1_AUDIO_SYNC);
if (diffs < THRESHOLD)
return DST_DIRECT_SLOT1_AUDIO;
diffs = compareBytes(bytes + 13U, DIRECT_SLOT2_AUDIO_SYNC);
if (diffs < THRESHOLD)
return DST_DIRECT_SLOT2_AUDIO;
diffs = compareBytes(bytes + 13U, DIRECT_SLOT1_DATA_SYNC);
if (diffs < THRESHOLD)
return DST_DIRECT_SLOT1_DATA;
diffs = compareBytes(bytes + 13U, DIRECT_SLOT2_DATA_SYNC);
if (diffs < THRESHOLD)
return DST_DIRECT_SLOT2_DATA;
return DST_NONE;
}
DMR_SYNC_TYPE CDMRSync::matchMSSync(const unsigned char* bytes) const
{
assert(bytes != NULL);
unsigned int diffs = compareBytes(bytes + 13U, MS_SOURCED_AUDIO_SYNC);
if (diffs < THRESHOLD)
return DST_MS_AUDIO;
diffs = compareBytes(bytes + 13U, MS_SOURCED_DATA_SYNC);
if (diffs < THRESHOLD)
return DST_MS_DATA;
return DST_NONE;
}
DMR_SYNC_TYPE CDMRSync::matchBSSync(const unsigned char* bytes) const
{
assert(bytes != NULL);
unsigned int diffs = compareBytes(bytes + 13U, BS_SOURCED_AUDIO_SYNC);
if (diffs < THRESHOLD)
return DST_BS_AUDIO;
diffs = compareBytes(bytes + 13U, BS_SOURCED_DATA_SYNC);
if (diffs < THRESHOLD)
return DST_BS_DATA;
return DST_NONE;
}
void CDMRSync::addSync(unsigned char* data, DMR_SYNC_TYPE type) const
{
assert(data != NULL);
const unsigned char* sync = NULL;
switch (type) {
case DST_BS_AUDIO:
sync = BS_SOURCED_AUDIO_SYNC;
break;
case DST_BS_DATA:
sync = BS_SOURCED_DATA_SYNC;
break;
case DST_MS_AUDIO:
sync = MS_SOURCED_AUDIO_SYNC;
break;
case DST_MS_DATA:
sync = MS_SOURCED_DATA_SYNC;
break;
case DST_DIRECT_SLOT1_AUDIO:
sync = DIRECT_SLOT1_AUDIO_SYNC;
break;
case DST_DIRECT_SLOT1_DATA:
sync = DIRECT_SLOT1_DATA_SYNC;
break;
case DST_DIRECT_SLOT2_AUDIO:
sync = DIRECT_SLOT2_AUDIO_SYNC;
break;
case DST_DIRECT_SLOT2_DATA:
sync = DIRECT_SLOT2_DATA_SYNC;
break;
default:
return;
}
for (unsigned int i = 0U; i < 7U; i++)
data[i + 13U] = (data[i + 13U] & ~SYNC_MASK[i]) | sync[i];
}
unsigned int CDMRSync::compareBytes(const unsigned char *bytes1, const unsigned char* bytes2) const
{
assert(bytes1 != NULL);
assert(bytes2 != NULL);
unsigned int diffs = 0U;
for (unsigned int i = 0U; i < 7U; i++) {
unsigned char b = SYNC_MASK[i] & (bytes1[i] ^ bytes2[i]);
diffs += BITS_LOOKUP[b];
}
return diffs;
}